Lathe-dog



(No Model.)

G. EHRHARDT;

LATHE DOG.

No. 497,517. Patented May 16, 1893.

ATT

WIT/V5885?! I/Vl/E 70/? SW Gushml 'Ar/mrdt wt Mom's wrrzns co. ncroumcnWAEHXNGYDA u c UNITED STATES PATENT OFFICEO GUSTAVE EHRHARD'I, OFPITTSBURG, PENNSYLVANIA.

LATHE-DOG.

SPECIFICATION forming part of Letters Patent No. 497,517, dated May 16,1893.

Application filed July 16, 1891. Serial No. 399,761. (No model.)

hereby declare that the following is a full,

clear, and exact description of the invention, which will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification.

My invention relates to an improvement in lathe-dogs, and has for itsobject to provide a self-adjusting clutch-device, whereby, as the strainincreases, the dog will be caused to grip the article more firmly.

With this object in view, my invention consists essentially in anadjustable block, sliding in a yoke, and co-acting with a serratedcam-lever.

My invention consists, further in certain detailsof constr'uctionandarrangement which will be more particularly pointed out in connectionwith the drawings, wherein- Figure 1, is a face view of a lathe-dog,embodying my invention. Fig. 2, is a side view of the same. Fig. 3, isan end view.

Referring by letter to the drawings, A represents a yoke or guide-frame,having parallel side-bars, B B, which are provided with guiding webs OO, and D, represents a sliding block, which fits snugly in a rectangularopening, E, of the yoke, and is provided at its side edges withchannels, F, to engage the guiding webs. The yoke is provided at one endwith a collar, G, having a smooth bore or bearing,in which is mountedatubular adjustingnut, I-I, having its outer projecting end milled, asseen at I, and provided at its inner end with a lateral annular flange,J, to bear against the inner end of the collar, G. The tubular adjusting-nutistapped to engage the threaded shank or stem, K, which isattached at its inner end to the sliding block. The yoke is provided atthe opposite ends with parallel ears, L, between which fits thecam-lever, M. The

cam-lever is mounted upon a pivot-screw, N, which fits in registeringperforations, O O, in the parallel ears, L. The space, P, between theparallel ears, in which the cam-lever operates, communicates with therectangular opening, E, in the yoke, whereby the serrated cam-face ofthe lever projects into the said opening. The sliding block isintroduced into the rectangular opening through the space between theparallel ears, the cam-lever being subsequently inserted and engaged bythe pivot-screw. The face of the sliding block, opposite the cam-lever,is provided with a V- shaped notch, Q, to engage one side of the barwhich isto be clamped by the dog, the opposite side of said bar beingengaged by the serrated surface of the cam-lever. This bar is indicatedby dotted lines at R.

In operation,the sliding block is 1noved,by means of the adj Listing-nutuntil its forked or notched end engages one side of the bar, whereuponthe cam-lever is turned until its serrated surface bears against theopposite side of the bar and clamps the latter firmly against thesliding block. The cam-lever is locked in it's adjusted position bymeans of a pin which is indicated in dotted lines at S. The strain uponthe bar, R, is in the direction indicated by the dart in Fig. 1, and itwill be seen that as the strain increases the cam-lever will be operatedto clamp the bar more firmly in place, for the reason that the majordiameter of the cam will be brought more nearly into alignment with thediameter of the bar.

Having thus described my invention, what I claim, and desire. to secureby Letters Patent of the United States, is-

1. The combination with a supporting yoke having an opening providedwith side guiding webs, of a sliding block mounted upon the guiding websand provided with a threaded stem which is engaged by an adjusting nutwhich is permanently mounted on said yoke,

and a serrated cam mounted on the yoke in one end thereof, of asliding-block fitting in the yoke and having a V-shaped notch in itsface, and provided with a threaded stem to engage an adjusting-nut onthe yoke, substantially as specified.

3. In a lathe-dog, the combination with a guiding-yoke carrying acam-lever, of a sliding-block provided with a threaded stem, and atubular adjusting-nut fitting in a smoothbored collar, and engaging thethreaded stem, 10 substantially as specified.

In testimony whereof I affix my signature in the presence of twoWitnesses.

GUSTAVE EIIRHARDT.

Witnesses:

F. P. IIOWLEY, JOHN GRAEBING, Jr.

